Development of the genital ducts and external genitalia in the early human embryo.
Summary of "Development of the genital ducts and external genitalia in the early human embryo."
The course of development of the human genital tract is undifferentiated to the 9th week of development. At this time two symmetrical paired ducts known as the mesonephric (MD) and paramesonephric ducts (PMD) are present, which together with the urogenital sinus provide the tissue sources for internal and external genital development. Normal differentiation of the bipotential external genitalia and reproductive ducts are dependent upon the presence or absence of certain hormones. Masculinization of the internal and external genitalia during fetal development depends on the existence of two discrete testicular hormones. Testosterone secreted from Leydig cells induces the differentiation of the mesonephric ducts into the epididymis, vasa deferentia and seminal vesicles, whereas anti-Müllerian hormone (AMH) produced by Sertoli cells induces the regression of the paramesonephric ducts. The absence of AMH action in early fetal life results in the formation of the fallopian tubes, uterus and upper third of the vagina. In some target tissues, testosterone is converted to dihydrotestosterone, which is responsible for the masculinization of the urogenital sinus and external genitalia.
Reproductive Medicine Unit, St. Mary's Hospital Manchester, UK.
This article was published in the following journal.
Name: The journal of obstetrics and gynaecology research
- PubMed Source: http://www.ncbi.nlm.nih.gov/pubmed/20846260
- DOI: http://dx.doi.org/10.1111/j.1447-0756.2010.01272.x
Genital malformations occur at a high frequency in humans, affecting ~1:250 live births. The molecular mechanisms of external genital development are beginning to be identified; however, the origin of...
The move of vertebrates to a terrestrial lifestyle required major adaptations in their locomotory apparatus and reproductive organs. While the fin-to-limb transition has received considerable attentio...
To examine the sex assignment in patients with atypical external genitalia, a particularly challenging situation, especially when the genital appearance is not compatible with the sex chromosome.
Human papillomavirus (HPV) causes external genital lesions (EGLs) in men, including condyloma and penile intraepithelial neoplasia (PeIN). We sought to determine incidence, HPV genotype distributio...
Masculinization of external genitalia is an essential process in the formation of the male reproductive system. Prominent characteristics of this masculinization are the organ size and the sexual diff...
The purpose of this study is to determine whether imiquimod creams are effective in treating external genital warts (EGW). The secondary objective of this study is to provide information o...
The purpose of this study is to determine whether imiquimod creams are effective in treating external genital warts (EGW). The secondary objective of this study is to provide information ...
The implantation rate after frozen-thawed embryo transfer cycles depends mostly on the receptivity of the endometrium and the embryo quality.The effects of human chorionic gonadotropins (h...
Embryo culture is a cornerstone of in vitro fertilization treatments. Usually, embryos are cultured in microdrops of culture media in incubators with controlled temperature, humidity and a...
The purpose of this study is to compare the development of human embryos grown in a conventional culture dish to those grown in a new embryo culture device known as the SMART System.
Medical and Biotech [MESH] Definitions
A condition of sexual ambiguity in which the individual (pseudohermaphrodite) possesses gonadal tissue of one SEX but exhibits external PHENOTYPE of the opposite sex. Female pseudohermaphroditism is an individual with XX karyotype, normal development of OVARIES and internal reproductive tract, but with ambiguous or virilized external GENITALIA. Male pseudohermaphroditism is characterized by the presence of a Y CHROMOSOME and TESTES, but the genital tract and external genitalia are ambiguous or completely female.
Abnormalities in the development of the GONADS, the genital tracts, the external GENITALIA, and gender-specific behavior.
Early pregnancy loss during the EMBRYO, MAMMALIAN stage of development. In the human, this period comprises the second through eighth week after fertilization.
A pair of ducts near the WOLFFIAN DUCTS in a developing embryo. In the male embryo, they degenerate with the appearance of testicular ANTI-MULLERIAN HORMONE. In the absence of anti-mullerian hormone, mullerian ducts give rise to the female reproductive tract, including the OVIDUCTS; UTERUS; CERVIX; and VAGINA.
A pair of excretory ducts of the middle kidneys (MESONEPHROI) of an embryo, also called mesonephric ducts. In higher vertebrates, Wolffian ducts persist in the male forming VAS DEFERENS, but atrophy into vestigial structures in the female.